Method for applying powdered coatings

Abstract

Relatively small parts are powder coated without fixturing by placing the parts on a heat conductive surface and the powders are distributed over the exposed surfaces of the parts. The powders on the surfaces of the parts are heated to fuse the powders, as by radiant heat, while the heat conductive surface is kept at a temperature below that at which overspray powders on the conductive surface will become tacky. In a preferred embodiment, the heat conductive surface is an endless belt which advances the parts past a powder coating station, past a top heating-bottom cooling station and then to discharge.

I claim: 
     
       1. A method for applying powdered coatings to relatively small parts without fixturing, comprising the steps of: placing the parts on a heat conductive surface;   distributing the fusible coating powders over the exposed surfaces of the part;   heating the powders distributed on the parts to above their melting point while maintaining te heat conductive surface at a temperature below which any overspray coating powders on the conductive surface become tacky.   discontinuing the heating; cooling the powders below their melting point; and   removing the parts from the heat conductive surface after the coatings have solidified.   
     
     
       2. A method according to claim 1 wherein the heat conductive surface is an endless belt. 
     
     
       3. A method according to claim 2 wherein the parts are carried past a coating station and then past a top heatingbottom cooling station by forward movement of the belt. 
     
     
       4. A method according to claim 1 wherein the powders are distributed by spraying. 
     
     
       5. A method according to claim 4 wherein the powders are electrostatically sprayed. 
     
     
       6. A method according to claim 1 wherein the coatings are less than 0.002 inches thick. 
     
     
       7. A method according to claim 3 wherein the powder overspray is removed from the belt before receiving additional uncoated parts. 
     
     
       8. A method according to claim 1 wherein the coated parts are turned over and coated on their other sides. 
     
     
       9. A method according to claim 8 wherein the part are magnetically attractable and are turned over magnetically.